Printing-telegraph exchange system



Oct. 20, 1925. 1,557,609

:1. B. PERRY PRINTING TELEGRAPH EXCHANGE SYSTEM Filed Nov. 10. 1923 Mvemar:

flaw/a Z7. Perry W W m Patented Oct. 20, 1925.

UNITED STATES PATENT OFFICE.

DONALD B. PERRY, 0F YONKERS, NEW YORK, ASSIGNOR T0 AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

PRINTING-TELEGRAPH EXCHANGE SYSTEM.

Application filed November 10, 1923.

T0 (4Z5 whom it may concern:

lie it known that I, DONALD B. PERRY, residing at Yonkers, in the county of Westchester and State of New York, have invented certain Improvements in Printing- Telegraph Exchange Systems, of which the following is a specification.

This invention relates to printing telegraphy and more particularly to printing telegraph exchange systems.

An object of the invention is a provision of switching apparatus under the control of a plurality of printing telegraph stations for extending connections over a telegraph line in either direction between said stations.

In accordance with the preferred form, the present invention contemplates the provision of machine switching apparatus asso cirted with each end of a telegraph line which is equipped for duplex operation, and controlled by each 01" a plurality of printing telegraph stations for extending connections between the stations in either direction over said line.

In the single figure of the drawing, there is shown the apparatus associated with one end. of a telegraph line, and common to a plurality of printing telegraph subscribers.

In the drawing. there is shown a printing telegraph subscribers station A connected to a central station B by means of line conductors C, which terminate in machine switching apparatus and which are arranged to be extended over a telegraph line 10 to a di. ant station where apparatus identical to that shown in the drawing is located.

The nachine switching apparatus coma plurality of banks of contacts I), E, I G, H and I, which are arranged to be traversed by suitable wipers, whereby de si; ed circuits are under control oi the subscribe 's stations for extending desired connections. Leading from the contacts in the banks l) and E are conductors which ez-o tend to the contacts of the cut-oil relay in diridual to each of the subscribers lines, it being of course understood that a plurality oi lines similar to C extend from other subscribers stations to the central cities in which the machine switching apparatus is located.

lilach ot the suhscribefis stations is provided with a printing telegraph transi'nitter and rccei 'ing printer and an impulse sending device 8, the latter being employed for Serial No. 674,016.

the transmission of selective impulses for operating the machine switching apparatus to set up desired connections.

Assume for the sake of illustration, that the subscriber A desires to extend his line C to a subscriber located in a distant city in which the telegraph line 10 terminates. Subscriber A would operate switch 5 for causing the energization of switching relay 6 which disconnects at its contacts the ground connection and the call hell 7 and connects the transmitter, printer and impulse sending device 8 in series with the line C. Following the closure of the front contacts switching relay 6, an energizing circuit is established for line relay 12 extending from grounded battery, winding of line relay 12, upper contact and armature or cut-oil relay 13, right-hand armature and front contact of relay 6, transmitter and printer in series, contact 9 of the impulse sending device 8, left-hand front contact and armature of relay 6, and the lower armature and back con tact oi? relay 13 to ground. Line relay 12 is energized over the circuit traced and disconnects ground from the contact in the bank F corresponding to the calling subscribers line, and connects ground to the first contact in the bank of contacts H. The connection of ground to the first contact in the bank of contacts H establishes an energizing circuit for the slow-t-o-release relay 15 and the stepping magnet 16, extending from grounded battery, winding, armature and back contact of stepping magnet 16, upper winding of relay 15, first contact in the bank of contacts H and the front contact and armature of relay 12 to ground. Relay 15 and stepping magnet 16 will be operated over the circuit just traced. Relay 15 prepares a locking circuit for itself and for magnet 16 extending to ground through the F wiper and bank 0t contacts. The contacts in the bank of contacts F should be grounded tor all spare lines, while the other contacts will be connected to ground through the back contact and arn'iature of the line relay individual to each of the lines in the manner illustrated in the drawing.

On each energization of the stepping mag net 16, the back contact of the stepping Iii-agnet will be opened for causing the deenergi- Zation ot this magnet, whereupon a pawl attached to its armature will act against a ratchet to cause all six wipers F to I inclusive to advance one step. Inasmuch as relay 15 is of the slow-to-release type, it does not release its armatures on the opening of the contact at magnet 16. However, when the back contact of this magnet is again closed, a circuit for causing its energization is established through the wiper and grounded contacts in the bank F causing the further advancement of each of the wipers. Accordingly, the wipers will be advanced to a point where there is an absence of ground on the F wiper at which time the energizing circuit for the stepping magnet 16 will not Le completed and the further advancement of the wipers is prevented. In the particular selection chosen, the wipers would advance until. they engage contact 1st which is connected to the back contact of line relay 12 and which, owing to the operation of this relay, has absence of ground thereon.

When the terminals of the calling line are reached by the wipers, the slowto-release relay 15 will then release opening the circuit of the stepping magnet 16 and closing at its upper contact a circuit extending from grounded battery, winding of control relay 18, upper armature and contact of relay 21, uppermost armature and back contact of relay 15, wiper and contacts in the bank G, windings of cut-oil relays 19, 13 and in series to ground. Control relay 18 and cut-off relays 19, 13 and 20 will be energized over the circuit just traced. The cut-off relays, there being one of these relays associated with each of the subscribers lines, disconnect all the associated line relays and connect all the individual lines tothe contacts in the banks D and E allotted to the particular subscribers stations. As for example, the cut-off relay 13 connects through its front contacts to the bank of contacts D and E, the line C extending from the subscribers station A. The control relay 18 prepares a circuit for locking ringing cutoff relay 22 and energizing relay 23 and also transfers the circuit extending from the armature of differential relay 2 1 from the relay 21 to the release circuit through the bank of contacts H. Since the wipers have stopped at the terminals corresponding to the line C, only that subscribers line will be connected through to the ringing cut-oli' relay 22. The release of the line relay 12 will have no effect as relay 15 is now released, thereby preventing the reestablishment of the stepping circuit.

Ringing current will now be transmitted intermittently through the upper winding and upper back contact of ringing cut-oft relay 22, through the D wiper and subscribers terminal over the line C returning through the terminal and wiper on the connected contact in bank E through'the armature and associated back contact of the ringing cut-oil relay 22 to ground. The

ringing cutolt relay 22 will be operated immediately as this relay operates upon the establishment of a direct current path which is established upon the energization of cutoff relay 13.

Immediately upon the operation of ringing cut-oft relay 22 a locking circuit therefor is established from grounded battery, lower armature and front contact of control relay 18, winding of relay 23, lower winding and lowermost front contact and armature of cut-off relay 22 to ground. The ringing cut-off relay 22 and the relay 23 will be held energized until the calling subscriber disconnects. The ringing cut-off relay 22 connects the D wiper to the control winding of the pole changer relay 27 through the upper winding of the differential relay 2 1 and the upper armature and contact of control relay 29, while the wiper of the E set of contacts is connected through to the lower winding of differential relay 2 1. The subscriber A is new connected to the duplex apparatus associated with the telegraph line 10.

Differential relay 2% which had previously been locked up through resistance 25, which is disconnected upon the energization or cut oil relay 22 new releases as equal current flows through both of its windings. The release of differential relay 2%- has no effect at this time as its front and back contacts are both opened. Relay 23 is slow-to-oper ate and does not energize until after the diit'erential relay 2% has released. It nects ground to the trout contact of the dii'l'erential relay 2st, thus preparing a circuit for releasing the selector switch when the differential relay operates as described later.

As previously stated, the subscribers line C is connected through the contacts in the banks D and E and the wipers individual thereto to the apparatus associated with the telegraph line 10, which apparatus is now under control of the subscriber A.

The subscriber A now operates the impulse sending device 8 for opening and closing contact 9 a predetermined number of times in accordance with the number of the called for subscribers station, whereby the circuit of the control winding on the pole changer relay 27 is opened and closed. Due to the opening and closure of the energizing circuit of the pole changer relay 27, impulses are transmitted over the telegraph line 10 in accordance with the operation of the impulse sending device 8. These impulses pass over the telegraph line 10 and traverse the windings ot the receiving relay 28 located at the opposite end of the telegraph line 10. Receivin relay 28 responds to such impulses ano controls the operation of control relay 29 thereby causing the energization and deenergization of the differential relay 24 in accordance with the received impulses. As the impulses are received from the line, the differential relay at responds and each impulse will release this relay and close a circuit which may be traced from grounded battery, winding of stepping magnet 16, lower contact and armature of relay l5, winding of slowtorelease relay 21, upper back contact and armature of relay 1S, armature and back contact of differential relay 2d and the low ermost back contact and armature of relay 22 to ground. The closure of the circuit just traced at the back contact of the differential relay 242 causes the operation of stepping magnet 16 for advancing the wipers to the terminals corresponding to the number of impulses transmitted over the telegraph line due to the operation or the impulse sending device 8. hen these impulses have ceased, slow-to-release relay 21 releases, whereby the energizing circuit is established for the control relay 18 and, the cut-elf relays corresponding to those shown in the drawing to associate with subscribers lines terminating at the station in which the other end of the telegraph line 10 terminates.

The cut-oil relays connect all subscribers lines to their respective terminals in the l) and E banks and disconnects all line relays as previously described. The selected line will, however, be connected through the wipers individual to the D and E bank of contacts to the ringing cut-oil relay Ringing current will be transmitted intermittently over one side of the subscribers line for causing the operation of the call bell individual to the called-for subscribers station. The called-for subscriber due to the operation of the call bell is advised that another subscriber desires to communicate with him telegraphically and that the printer set should be connected with the line conductors by the operation oil? a switch corresponding to 5 which causes the operation of a. switching relay for connecting the transmitter and printer in series with the line conductors. As in the case of the outgoing calls when the switching relay is energized. a circuit for direct current through the upper winding of the ringing cut-oil relay is completed, whereby this relay is energized and locked up for disconnecting the source of ringing current 26. Relay 22 also removes the resistance from in series with the upper winding of the differential. relay 24 and establishes the circuit to the called for subscribers line. On this operation relay 2% releases and relay 23 operates for performing functions similar to that described at the outgoing end and the two subscribers are new connected and may con'm'iunicate telegraphically by the operation of their printing telegraph apparatus.

lVhen the calling subscriber A discern nects his printer ecpiipment, by the opening of switch 5 after a comn'iunication is completed or in abandoning a call, ground is connected to one side of the line circuit C, and the other side of this line circuit is left open to direct current. This action operates the dil'lerential relay 24. over a circuit extending from battery, lower winding of differential relay 241:, front contact of armature of ringing cut-oft relay 22, wiper and connected contact in the bank E, lower front contact and armature oi cut-oil relay 13, left-hand armature and back contact of relay 6 to ground. The dili'erential relay 24- closes a circuit for the slow-to-release relay 15 and the stepping iagnet 16 through the bank of contacts H and the upper front. contact and armature of control relay 18. Relay 15 will operate over the circuit just traced and will loel; itself up through the wiper and contacts in the bank F which are all grounded at this time. The stepping magnet 16 will operate and step the wipers around to their normal position. Due to its slow-to-i'elease "feature, relay 15 will remain operated during the intervals when the stepping magnet 16 opens its circuit at its armature. The relay 15 opens at its upper armature the energizing circuit of the contol relay 18 and the cutoll' relays which are now released. The cut-ofi relays disconnect all subscribers lines from the bank of contacts I) and E to prevent the operation of the call bells at each or the stations as the wipers rotate over the respective con tacts. The release of the control relay 18 opens the locking circuit of the ringing cutofii relay 22 and relay 23, which are thereupon released, reconnecting the resistance 25 in circuit with the upper winding of the diitlerential relay 24E.

lVhen the called subscriber disconnects, ground is connected to one side of the line circuit, leaving the other side of this line circuit open to direct current. The resto ration of the selector switch to normal is similar to that described in connection with the disconnection of the calling subscriber. Further description is therel'ore thought un necessary.

During the interval from the time the subscriber A disconnects the printer equipment from the line to the moment that the resistance 25 is: com'iected in circuit with the upper winding of: the diiierential relay 24;, the pole changer relay 27 is deenergized for transmitting over the telegraph line 10 a spacing impulse. This spacing impulse upon being received at the incoming end of the line causes the operation of the receiving relay 28 and the release oi the control relay The diti'crei 'al relay 2a at the incoming end of the line will be energized for causing the: energization oi. slow-to-rebe restored to normal.

lease relay 15 and the stepping magnet 16, as previously described. The incoming selector will thus be restored to its normal po-. ition, the restoration of the selector at the outgoing end of the line being similar to that previously described.

It often happens that one subscriber may disconnect before the other, thereby restoring the selector switch to normal before the second subscriber disconnects. Due to thefact that the telegraph circuit is opened for a short interval after a, subscriber discon nects, the differential relay of the selector associated with the line of the first subscriber to disconnect, will release and later operate when the telegraph line is closed. This, in turn, operates and releases relay 21 and the stepping magnet 16, thereby step ping the wipers of the selector at the first station to disconnect on to the second set of contacts. A circuit is at once completed to operate relay l5 and restore the selector to normal in the manner previously described.

It occasionally occurs in regular service that the telegraph line may be opened for an interval. This may be caused by any one of a number of conditions such as an accidental operation of a key, a swing on the line, etc. The effect at both stations of such an open circuit would be similar to the delayed disconnect, previously described. The duration of the open condition will not affect the procedure as long as the circuit closes eventually, at which time it will It is thus seen that the circuit provides for a return to normal after a false or accidental opened circuit, as well as a delayed disconnect by either subscriber.

Should the subscriber A operate the impulse sending device 8 in error, as to select a set of unused terminals, a clear-out circuit is provided whereby the selector will re store the system to normal. All of the terminals in the bank 1 corresponding to the unused lines are grounded and when the wiper stops on any one of these terminals and relay 21 is released, relay 15 is energized through its lower winding, restoring the selector to its normal position.

Should th calling subscriber disconnect the printer equipment before the selector has reached the terminals corresponding to the calling line, the wipers will continue to rotate until they again reach the normal position. If the call is abandoned after the line has been seized and before the operation of the impulse sending device 8, the outgoing selector will be released in the normal manner and an impulse will be transmitted over the telegraph line 10 causing the wipers at the distant station to make one revolution.

When the telegraph line is in use, all of the cut-off relays will be energized at both stations, thus removing the battery and ground connections from all of the local lines. If a subscriber attempts to extend a connection at this time, it will be found that the line circuit is in use and the action of the receiving printer will serve to notify such subscriber of this condition. The same condi'tion exists when the subscribers line is busy.

Although the invention has been described with reference to a particular system, it is of course obvious that various modifications may be made without departing from the spirit and scope of the present invention.

hat is claimed is:

1. In a telegraph system, a plurality of printing telegraph stations, each provided with a receiving printer and transmitter, a telegraph line, and switching mechanism common to said stations and under the control of any of said stations for extending connections in either direction oversaid line between said stations.

2. In a telegraph system, a plurality of printing telegraph stations, each provided with a receiving printer and transmitter, a telegraph line, and a single switching mechanism common to said stations and under the control of any of said stations for extending connections in either direction over said line between said stations.

3. In a telegraph system, a plurality of printing telegraph stations, each provided with a printing telegraph transmitter and receiving printer, a local line individual to each of said stations extending thereform to a central station, a telegraph line terminat ing at said central station, switching mechanism normally disconnected from said local lines, and means operative upon the connection of the transmitter and receiving printer with any one of the local lines for causing said switching mechanism to automatically extend the line from said station to said telegraph line.

4. In a telegraph system, a plurality of printing telegraph stations, each provided with a printing telegraph transmitter and receiving printer, a local line individual to each of said stations extending therefrom to a central station, a telegraph line terminating at said central station, switching mechanism normally disconnected from said local lines, switching mechanism directly connected to said telegraph line, means responsive to the connection of the transmitter and receiver with a local line for automatically causing the operation of said switching mechanism to a predetermined point, and means operative due to the positioning of said switching mechanism to a predetermined point for connecting all of said local lines to said switching mechanism and extending the connected station through to the telegraph line.

In a telegraph system, a plurality of telegraph stations, each provided With a receiving printer and transmitter, a telegraph line, switching mechanism common to said stations and under the control of any of said stations for extending connections in either direction over said line between said stations, and means operative upon a mo mentary accidental opening of said line for restoring said switching mechanism to normal to again be in readiness for the extension of further connections.

6. In a telegraph system, a plurality of telegraph stations, each provided With a receiving printer and transmitter a telegraph line, switching mechanism common to said stations and under the control of any of said stations for extending connections in either direction over said line between said stations, and a differential relay associated with each end of said tele raph line and operative upon a momentary accidental opening of said line for restoring said sivitclr ing mechanism to normal to again be in readiness for the extension of further connections.

In testimony whereof, I have signed my name to this specification this 8th day of November, 1923.

DONALD B. PERRY. 

